The present invention relates to a vehicle seat of the type comprising:
at least one electrically powered functional member which functional member comprises:
an active element designed to perform a unique elemental function;
a local control unit for controlling an active element of the functional member from commands;
means of receiving commands, which receiving means are incorporated into the said functional member; and
means for collecting operational status data from the functional member; and
a communication bus to which each of the receiving means of the or of each functional member is directly connected for transmitting commands.
It relates in particular to vehicle seats which can be used for example in passenger aircraft.
These seats generally comprise a seat cushion, to one end of which an inclinable back-rest is articulated. Articulated to the other end of the seat cushion is a leg-rest, extended by a foot-rest, both of which latter rests can move.
The seat is equipped with electric actuators so as to move the various elements thereof with respect to one another.
In the state of the art, in order to control the dynamics of the seat, a central control unit is provided on each seat and this central unit powers each of the actuators of the seat so as to move them in a determined direction, at a given speed and for a given time.
Furthermore, in order to determine the position of each element of the seat, each actuator is equipped with a transducer such as a potentiometer supplying data representative of its operational status.
This transducer is connected to the central control unit so that the status data collected can be exploited.
The presence of the supply wires and the communication wires for transmitting status data leads to there being a very large number of wires in the seat.
In practice, these wires are gathered together to form looms which are relatively bulky and difficult to conceal within the seat.
In order to reduce the number of supply wires, it is known practice, for example from document EP-A-1.010.570, to provide a bus for transmitting commands to each of the actuators, the commands being transmitted by a control unit connected to the bus. To supply electrical power, each actuator is powered directly from an electrical power supply line.
The proposed solution admittedly makes it possible to reduce the number of supply wires, but does not make it possible to perform complex dynamics of moving the various elements of the seat, particularly synchronizing the movements of these elements.
Elsewhere, document U.S. Pat. No. 4,706,194 describes a multiplex control system for a seat in which a two-way bus is used. A central control unit is provided on this bus for controlling the actuators of the seat.
A multiplexing unit is connected to the bus and each of the actuators is connected to the multiplexing unit, on the one hand, for controlling it and, on the other hand, so that the actuator can transmit operational status data.
Thus, for each actuator, the multiplexing unit has inputs and outputs specific to the actuator and to which the actuator is connected.
This being the case, there are numerous connecting wires between the multiplexing unit and each actuator. There are therefore still wiring looms inside the seat, ever though they do not directly connect the central control unit to each of the actuators.
Hence, in the arrangement described in that document, there is a relatively dense wiring loom between the multiplexing unit and each of the actuators, thus removing the benefit to using a bus.
It is an object of the invention to propose a vehicle seat comprising a set of functional members that can be controlled individually or with synchronization between the operation of the various functional members, and which does not require the use of bulky wiring.
To this end, the subject of the invention is a vehicle seat of the aforementioned type, characterized in that at least one functional member comprises operational status data transmission means which transmission means are incorporated into the said functional member and are each directly connected to the communication bus for transmitting operational status data on the communication bus.
According to some particular embodiments, the seat has one or more of the following characteristics:
it comprises a central data processing unit which central data processing unit comprises, on the one hand, means of transmitting commands which means are connected to the communication bus for transmitting at least one command to at least one functional member and, on the other hand, means of receiving operational status data, which means are connected to the communication bus for receiving operational status data transmitted by the or each functional member;
the said central data processing unit comprises means of analysing the operational status data received and means of formulating commands for at least one functional member;
the said analysis means are designed to analyse jointly operational status data from at least two functional members;
the or each functional member is one of the members chosen from the group consisting of: an actuator, a heating member, a massage device, an inflatable cushion, a lighting device, a keypad and an item of audiovisual equipment;
the communication bus is a bus of the serial type; and
it comprises at least one functional member which has no active element designed to exert an elemental function, the or each functional member comprising means of collecting operational status data from the functional member.